Caisson

ABSTRACT

A caisson for marine works particularly intended for use in vertical dikes which is formed by a plurality of segments ( 1 ) meant for being joined co-laterally therebetween by joining means to form a ground slab, wherein the segments ( 1 ) comprise an internal sector ( 2 ), lateral sectors ( 3 ) and an external sector ( 4 ), where said external sector ( 4 ) incorporates coupling elements; and by a series of voussoirs ( 5 ) meant for being disposed co-laterally therebetween and on the ground slab to form a surface of revolution, having an upper side ( 6 ), lateral sides ( 7 ) with interlocking means for interlocking the voussoirs ( 5 ) therebetween and a lower side ( 8 ) meant for being inserted in the segment ( 1 ) coupling elements. All of the caisson&#39;s elements are manufactured from fibre-reinforced polymer materials.

OBJECT OF THE INVENTION

The present invention can be included in the technical field of vertical caissons used in marine works. More specifically, it is a prefabricated caisson made of a fibre-reinforced polymeric material that is dry assembled in port.

BACKGROUND OF THE INVENTION

In port works, dikes are a structure used with the object of reflecting and dissipating wave energy, thereby preventing or reducing the action of waves in an area to be protected. There are two basic types of conventional dikes: sloping dikes and vertical dikes.

Sloping dikes are structures built at sea to provide shelter to a certain area. These dikes consist of natural and/or artificial breakwaters of different sizes, usually concrete shoulders.

Vertical dikes are monolithic structures having vertical surfaces and impermeable walls. Said dikes are built using reinforced concrete caissons and have gravitational behaviour, i.e. the stability of the caisson is based on its own weight. The essential characteristic of vertical dikes is that they reflect practically all wave energy, reflecting wave action in the manner of a rigid vertical monolithic wall.

The most common solution to the construction of vertical dikes is the use of prefabricated reinforced concrete caissons, which are manufactured at sea and transported by floatation to their definitive location, where they are anchored. The use of caissons in these constructions also allows the formation of dikes and piers for mooring vessels and for containment of fillings for obtaining surface platforms.

When working with caissons, these are anchored to the seabed by means of stone filling banks that transmit very high pressures to the natural terrain of ports. In the case of ports, the high load increase caused by the addition of the weight of the caisson resting on the ground is very important, as in some cases it has led to breakage or sliding.

The execution of a vertical dike entails multiple advantages with respect to the execution of a sloping dike. It requires a smaller amount of added material as it is a body of smaller size, which reduces environmental impact and the cost of the works. It also occupies less space on the seabed, allowing mooring of vessels, and also contributes to reducing environmental impact, generating less turbidity during the construction phase and subsequent operation thereof.

Vertical dikes allow shorter execution times. Likewise, they require less maintenance than breakwaters and allow better finishes and are better adapted for a wider range of uses.

The most significant constraints to vertical dikes are their dependence on caisson vessels for construction thereof, the manufacturing cost of which is very high. Additionally, the caisson vessel must be transported to a location near the anchoring location of the caissons for each work. These costs can be very high and could even compromise the profitability of a project.

Another disadvantage is that sophisticated machinery and qualified labour is required, particularly for the construction of the caisson in the caisson vessel. Additionally, small variations in density can lead to significant differences in the floatability and stability of the caisson in the water, which are essential characteristics in order for the caisson to be safely towed to its anchoring position.

The caissons known in the state of the art have cells in the interior thereof, which are generally rectangular or circular cells. The caissons are generally built on floating facilities which can be floating dikes, submersible pontoons guided from fixed structures or catamarans with submersible platforms.

The usual caisson construction process consists of pouring the concrete ground slab for subsequently casting the caisson shaft using sliding formwork. As the caisson is being cast it is submerged in the water. It is then transported to its final location by a bow pushing tugboat. A complementary tugboat can also be used on the stern to act as a rudder. Once the caisson reaches its final location it is anchored to fix it in its definitive position.

DESCRIPTION OF THE INVENTION

The present invention proposes a caisson for marine works which can be used in all types of works but is particularly intended for use in vertical dikes.

The caisson for marine works consists of a modular construction comprising, as a base, a ground slab that can be circular or polygonal. The ground slab is formed by a plurality of segments meant for being correlatively joined together by joining means. Said segments comprise an internal sector, lateral sectors and an external sector that includes coupling elements. The segments that form the ground slab are identical.

In the case of polygonal ground slabs, the segments have a triangular or truncated triangular configuration. In the case of circular ground slabs, the segments have a radial segment configuration.

Likewise, the caisson comprises a series of voussoirs meant for being disposed co-laterally therebetween throughout the perimeter and on top of the ground slab to form a closed surface. The voussoirs have an upper side, lateral sides and a lower side. The lateral sides have interlocking means to allow the voussoirs coupling therebetween. The lower side is meant for fitting in the segment coupling elements.

In a preferred embodiment, the surface created through the co-lateral joint of the voussoirs is cylindrical.

An essential characteristic of the proposed caisson is that its constituent parts, i.e. the segments and voussoirs, are manufactured from fibre-reinforced polymer materials. Said parts are factory-made and are subsequently transported to the assembly location of the caisson, which is preferably a port near its final position. In this manner, once the assembly of the caisson has been completed it is launched from the pier and towed to its final position, where it is anchored.

The parts that form the caisson are dry assembled and the different joining means used to join the parts together can be mechanical joining means, such as for example dovetailing between the parts or rivets. They can be chemical joining means, such as a seawater-resistant adhesive or lamination using the caisson's own fibre and resin but executed onsite giving the part continuity. Likewise, the joining means can be a combination of mechanical and chemical joining means.

The voussoirs can be single-walled or double-walled. The election of one type of voussoir over another will depend, for example on the resistance required in each application, manufacturing conditions, total caisson dimensions, etc.

In the case of single-walled caissons, these may comprise vertical stiffeners that provide greater structural resistance to the caisson.

In the case of double-walled caissons, these comprise an outer wall and an inner wall joined together at least by the lateral sides of the voussoir, and can be open on the upper side and lower side thereof. In the case of double-walled voussoirs, the cavity remaining between the outer wall and the inner wall can be used to introduce a ballasting material for the caisson towing stage, for anchoring thereof, or the caisson can be filled to achieve greater resistance. Likewise, the segments can comprise a receptacle in the interior thereof wherein the lower side of the voussoirs can be introduced.

In an embodiment of the invention, the ground slab additionally comprises a central body, also manufactured from a fibre-reinforced polymer, whereto the internal sectors of the segments are joined by corresponding joining means. The central body may be cylindrical or prismatic.

Another object of the present invention is a process for assembling the previously described caisson for marine works. Said process comprises the stages of joining the segments co-laterally using joining means and joining the voussoirs co-laterally therebetween using the voussoir interlocking means, inserting the lower side of the voussoirs in the segment coupling elements. In an embodiment of the invention, the process comprises the introduction of stiffeners in the interior of the main space, which is the space created in the interior of the surface of revolution created by the voussoirs.

In a preferred embodiment of the invention, the segments and voussoirs are transported to a pier where they will be assembled. The parts are transported to the pier where they are dry assembled. When performing the assembly on a pier, once the caisson has been fully formed, implementation thereof comprises launching the caisson, ballasting the caisson by partially filling the main space, towing the caisson by floating to its final location and anchoring the caisson by filling the main space.

The parts are dry assembled with the help of a crane. This reduces costs because specialised labour for performing deep-sea or underwater work is not required. Additionally, assembly operations are considerably simplified and full assembly can be performed in a very short time.

Likewise, this avoids the use of caisson vessels which, as explained earlier, are very expensive and require a large investment. In this regard, there is greater independence as the caisson is assembled on the pier until the parts are transported by road, reducing costs and achieving simpler transport. Subsequently, when the caisson has been fully assembled it is launched and transported to its final location by towing. Therefore, it is not necessary to build floating facilities, such as for example floating dikes, submersible pontoons or catamarans with submersible platforms.

DESCRIPTION OF THE DRAWINGS

In order to complement the description being made and with the object of helping to better understand the characteristics of the invention, in accordance with a preferred embodiment thereof, said description is accompanied, as an integral part thereof, by a set of drawings where, in an illustrative and non-limiting manner, the following has been represented:

FIG. 1 shows a view of a voussoir of the caisson for marine works.

FIG. 2 shows a view of the ground slab of the caisson for marine works.

FIG. 3 shows a perspective view of the caisson for marine works.

PREFERRED EMBODIMENT OF THE INVENTION

The present invention describes a caisson for marine works and an assembly process thereof. Said caisson is specially designed for being used in vertical dikes.

The parts that integrate the proposed caisson (14) are a plurality of segments (1) that constitute the caisson ground slab and a series of voussoirs (5) that create a surface in the interior whereof a main space (15) is created which can be filled. The segments (1) and voussoirs (5) are manufactured from fibre-reinforced polymer materials. The material is preferably selected from among fibreglass or carbon fibre with an epoxy resin or polyester matrix.

In a preferred embodiment the segments form a circular ground slab and in another embodiment the segments form a polygonal ground slab. In the case of the circular ground slab, the segments (1) are circular segments and in the case of the polygonal ground slab the segments (1) have a triangular or truncated triangular shape.

The segments (1) are meant for being joined co-laterally therebetween by joining means to form the ground slab. Said segments (1) comprise an internal sector (2), lateral sectors (3) and an external sector (4) that includes coupling means.

The voussoirs (5) are meant for being joined together on the perimeter of the ground slab to form a closed surface. They have an upper side (6), lateral sides (7) and a lower side (8). The lateral sides (7) have means for interlocking the voussoirs (5) to allow these to be joined together and the lower side (8) is meant for fitting into the segment (1) coupling elements to allow the joint between the voussoirs (5) and the segments (1).

In an embodiment of the invention, the ground slab of the caisson also comprises a central body (9) which is also manufactured from a fibre-reinforced polymer material, whereto the internal sectors (2) of the segments (1) are joined by their corresponding joining means. In this embodiment, the internal sectors (2) have a geometric shape that matches the shape of the central body (9).

In an embodiment of the invention, the voussoirs (5) have a geometric shape that matches the shape of the external sector (4) of the segments (1).

The joining means used to fix the segments (1) therebetween and the voussoirs (5) therebetween and to the segments (1) may be chemical joints, such as for example a seawater-resistant adhesive or mechanical joints, such as for example dovetailing or rivets or a combination of the two.

In an embodiment of the invention, the segments (1) comprise a receptacle (12) that is in contact with the external sector (4) meant to house the lower side (8) of the voussoirs (5). This embodiment ensures a better fixation of the elements as, in addition to the use of joining means, the voussoirs (5) are inserted in the segments (1).

In an embodiment of the invention, the voussoirs (5) are single-walled and may comprise longitudinal stiffeners to give them greater structural resistance. In a preferred embodiment of the invention, the voussoirs (5) are double-walled and comprise an outer wall (10) and an inner wall (11). Said walls are joined together by their lateral sides (7), creating an internal space (13). The internal space (13) can be partially or fully filled, for example with granular material, for ballasting during the towing phase or for anchoring.

In another embodiment of the invention, the caisson (14) also comprises stiffeners in the interior of the main space (15). These stiffeners are diametric flat elements meant for joining opposing voussoirs (5) and giving greater resistance and rigidity to the entire caisson (14) assembly.

Likewise, another object of the invention is a process for assembling the previously described caisson, comprising the following stages:

-   -   joining the segments (1) co-laterally using joining means; and     -   joining the voussoirs (5) co-laterally therebetween using         interlocking means that interlock the voussoirs and the segments         (1), interlocking the lower side (8) of the voussoirs (5) with         the segment coupling elements to form a body of revolution.

In the embodiment of the invention wherein the ground slab comprises a central body (9), the assembly process comprises a joining stage in which the segments (1) are joined to the central body (9).

As mentioned earlier, in a preferred embodiment the caisson (14) is fully assembled in dry docks and in an even more preferred embodiment said assembly is performed on the pier near the final location of the caisson. To this end, the segments (1) and voussoirs (5) are transported to said pier.

In the embodiment of the invention wherein the segments (1) comprise a receptacle (12), the process comprises a stage in which the lower side (8) of the voussoirs (5) is introduced in the interior of the receptacle (12) of the segments (1) during the stage in which the voussoirs (5) are joined to the segments (1).

Likewise, in the embodiment wherein the caisson (14) comprises stiffeners, the assembly process comprises a stage in which stiffeners are introduced in the interior of the main space (15).

Subsequently, once the parts of the caisson (14) have been assembled, the process of the invention comprises the following stages:

-   -   launching the caisson (14);     -   ballasting the caisson (14) by partially filling the main space         (15);     -   towing the caisson (14) by sea to its final location; and     -   anchoring the caisson (14) by filling the main space (15). 

1. A caisson for marine works particularly intended for use in vertical dikes, characterised in that it comprises: a plurality of segments (1) meant for being co-laterally joined therebetween by joining means to form a ground slab, wherein the segments (1) comprise an internal sector (2), lateral sectors (3) and an external sector (4) wherein said external sector (4) incorporates coupling means; and a series of voussoirs (5) meant for being disposed co-laterally therebetween and on the perimeter of the ground slab to form a closed surface in the interior of which a main space (15) is created, having an upper side (6), a lower side (8) and lateral sides (7), having interlocking means for interlocking the voussoirs (5) therebetween, the lower side (8) of which is meant for being coupled to the segments (1); the segments (1) and voussoirs (5) are manufactured from fibre-reinforced polymer materials.
 2. A caisson for marine works, according to claim 1, wherein the voussoirs (5) also comprise an outer wall (10) and an inner wall (11) joined together by means of the lateral sides (7), creating an internal space (13).
 3. A caisson for marine works, according to claim 1, wherein the segments (1) form a polygonal ground slab.
 4. A caisson for marine works, according to claim 1, wherein the segments (1) form a circular ground slab.
 5. A caisson for marine works, according to claim 1, additionally comprising a central body (9), also manufactured from fibre-reinforced polymer materials, that forms part of the ground slab, whereto the internal sectors (2) of the segments (1) are joined by corresponding joining means.
 6. A caisson for marine works, according to claim 1, wherein the joining means used are seawater-resistant chemical joining means.
 7. A caisson for marine works, according to claim 1, wherein the joining means are rivets.
 8. A caisson for marine works, according to claim 1, wherein the joining means are dovetail joints.
 9. A caisson for marine works, according to claim 1, wherein the joining means are any combination of seawater-resistant adhesives, rivets and dovetail joints.
 10. A caisson for marine works, according to claim 1, wherein the segments (1) comprise a receptacle (12) that is in contact with the external sector (4) meant for housing the lower side (8) of the voussoirs (5).
 11. A caisson for marine works, according to claim 1, wherein the voussoirs (5) comprise longitudinal stiffeners.
 12. A caisson for marine works, according to claim 1, wherein the fibre reinforced with polymer materials is selected from among fiberglass and carbon fibre with epoxy resin or polyester.
 13. A caisson for marine works, according to claim 1, wherein the internal sector (2) of the segments (1) has a geometric shape that matches the shape of the central body (9).
 14. A caisson for marine works, according to claim 1, wherein the voussoirs (5) have a geometric shape that matches the shape of the external sector (4) of the segments (1).
 15. A caisson for marine works, according to claim 1, wherein it additionally comprises a plurality of stiffeners in the interior of the main space (15).
 16. A process for assembling a caisson for marine works such as that described in claims 1 to 15, wherein it comprises the following stages: joining the segments (1) co-laterally therebetween using the joining means; joining the voussoirs (5) co-laterally therebetween using the joining means for joining the voussoirs (5) and to the segments (1) interlocking the lower side (8) with the segment coupling elements to form a revolving body.
 17. An assembly process, according to claim 16, wherein it comprises a stage of joining the segments (1) to the central body (9).
 18. An assembly process, according to claim 16, wherein the segments (1) and the voussoirs (5) are transported to a pier where the assembly will take place.
 19. An assembly process, according to claim 16, wherein it comprises a stage of inserting the lower side (8) of the voussoirs (5) in the interior of the receptacle (12) of the segments (1) during the stage of joining the voussoirs (5) to the segments (1).
 20. An assembly process, according to claim 16, wherein it subsequently comprises a stage in which stiffeners are inserted in the interior of the main space (15).
 21. An assembly process, according to claim 16, wherein the stiffeners are diametric flat elements meant for joining opposing voussoirs (5) together, giving the caisson (14) greater resistance and rigidity once assembled.
 22. An assembly process, according to claim 16, wherein it subsequently comprises the following stages: launching the caisson (14); ballasting the caisson (14) by partially filling the main space (15); towing the caisson (14) by sea to its final location; and anchoring the caisson (14) by filling the main space (15). 